VMS Help WAIT, Parameter  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 delta-time

    Specifies a delta time interval in the following format. (A delta
    time is an offset from the current time to a time in the future.)

    hour:minute:second.hundredth

    The fields on the format line indicate the following:

    hour       Specifies an integer in the range 0 to 23.
    minute     Specifies an integer in the range 0 to 59.
    second     Specifies an integer in the range 0 to 59.
    hundredth  Specifies an integer in the range 0 to 99.

    The colons (:)  and period (.) are required delimiters; also, the
    delta time must begin with the number of hours and not a colon.
    Note that the days field, usually included in the delta time
    format, must be omitted here.

    For more information on specifying delta time values, refer
    to the OpenVMS User's Manual or the online help topic DCL_Tips
    (subtopic Date_Time).

    Note that if you enter the WAIT command interactively, you are
    not prompted for a time value; however, in order for the command
    to have any effect, you must supply a time value.